Access to the knee and shoulder capsules during arthroscopic surgery is typically made through opposing portals often called the operative portal and the visualization portal. The arthroscope is typically inserted through the visualization portal, while the medical device is inserted through the operative portal. The visualization portal can be readily interchanged with the operative portal to provide an enhanced view of and access to internal capsular structures.
The hip is complex and difficult to access using arthroscopic techniques. FIGS. 1 and 2 illustrate the basic anatomy of the hip. For the sake of simplification, the figures do not show the surrounding synovial membrane, the femor ligament complex, the tough adductor muscle structure, varying layers of fat, and other tissue, which all compound the difficulty in accessing the joint capsule. There are also many delicate structures surrounding the joint that are not shown in the figures, i.e., the anterior femoral neurovascular bundle, the lateral femoral cutaneous nerve, the lateral femoral circumflex artery and the sciatic nerve, among others. Damage to these structures is permanent and irreparable
Typically, access to the hip joint for minimally invasive arthroscopic surgery is through two cannulas positioned in the posterolateral and anterolateral positions that are located 1-2 cm above (superior) and 1-2 cm on each side of the landmark greater trocanter, as shown in FIG. 3. Typically, the arthroscope is in the posterolateral position and the operative device (e.g. forceps, dissector, scissors, scalpel, punch, probe, powered shaver, manual graspers, electrocautery wand, etc.) is in the anterolateral position. It is common to interchange these positions to improve visualization and/or access to the target site.
Despite the ability to interchange positions, parts of the distended surfaces of the hip joint can not be fully visualized. FIG. 3 shows this “No See” zone. The portions of the hip not accessible by straight and rigid operative instruments is even larger. For example, if the target site is in a region that is hidden on the far side of the femoral head, a third portal must often be established in the anterior position. Such an added portal considerably increases the risk of the procedure because the proximity of the lateral femoral cutaneous nerve, the lateral femoral circumflex artery, and the femoral neurovascular bundle. Access via the opposite, posterior side of the joint, i.e. the gluteal region, is not a viable option nor is the medial approach from the groin.
Roughly half of the distended hip joint is not accessible through the normal, accepted, portal placement positions. While the situation can be relieved somewhat through the use of 70 degree scopes and physically prying the cannulas into a contrived position, the access problem remains a significant hurdle to the performance of arthroscopic procedures on the hip.